To collect vaporized fuel in a fuel tank, a canister is communicably connected to the fuel tank. Fuel which is collected by the canister is fed to an engine by way of a carburetor. A vaporizing device of a scooter provided with such a canister is known (see JP-A-5-124560, for example).
In JP-A-5-124560, there is the description that a large negative pressure is applied to an intake side of a carburetor at the time of rapid acceleration of a scooter or the like and hence, the negative pressure is transmitted to the inside of a canister by way of a purge hose, a vaporized fuel gas accumulated in the canister is sucked into the carburetor through the purge hose, and is fed to the engine and is burnt. Accordingly, an air/fuel mixture becomes rich temporarily thus enhancing the acceleration property of the scooter.
According to JP-A-5-124560, the canister is arranged close to an engine unit. In this case, to maintain the collection performance of the canister, it is desirable to block heat from the engine.